Foldable chair frame

ABSTRACT

A foldable chair frame includes a seat, a backrest, left and right armrests, left and right pivot joints, and front and rear legs. The backrest is coupled pivotably to the seat. Each of the left and right armrests is coupled pivotably to the backrest. Each of the left and right pivot joints is coupled to a respective one of the left and right armrests and has front and rear pivot portions. The front leg is coupled pivotably to the front pivot portions of the left and right pivot joints. The rear leg is coupled pivotably to the rear pivot portions of the left and right pivot joints.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a chair frame, more particularly to a foldable chair frame.

2. Description of the Related Art

FIG. 1 illustrates a conventional foldable chair frame 1, such as that disclosed in Taiwanese Application no. 93206165. The conventional foldable chair frame 1 includes a seat 15, a backrest 12, left and right armrests 11, left and right plate members 17, front and rear legs 13, 14, and left and right fastening units 18.

The backrest 12 is coupled pivotably to the seat 15.

Each of the left and right armrests 11 is coupled pivotably to the backrest 12.

Each of the left and right plate members 17 is connected to a respective one of the left and right armrests 11, and is formed with an elongated hole unit 170 defined by a hole-defining wall unit 171.

The front leg 13 includes left and right rod members 131, each of which has an upper end.

The rear leg 14 includes left and right rod members 141, each of which has an upper end connected pivotably to a respective one of the left and right rod members 131 of the front leg 13.

The left fastening unit 18 extends through the elongated hole unit 170 in the left plate member 17 and the upper end of the left rod member 131 of the front leg 13, and is operable so as to fasten releasably the upper end of the left rod member 131 of the front leg 13 to the hole-defining wall unit 171 of the left plate member 17.

The right fastening unit 18 extends through the elongated hole unit 170 in the right plate member 17 and the upper end of the right rod member 131 of the front leg 13, and is operable so as to fasten releasably the upper end of the right rod member 131 of the front leg 13 to the hole-defining wall unit 171 of the right plate member 17.

When the conventional foldable chair frame 1 is disposed at a sitting position, each of the left and right fastening units 18 abuts against a rear end of the hole-defining wall unit 171 of a respective one of the left and right plate members 17.

With further reference to FIG. 2, when the conventional foldable chair frame 1 is disposed at a reclining position, each of the left and right fastening units 18 abuts against a front end of the hole-defining wall unit 171 of a respective one of the left and right plate members 17.

The aforementioned conventional foldable chair frame 1 is disadvantageous in that the upper ends of the left and right rod members 141 of the rear leg 14 are bent so that the front and rear legs 13, 14 may be disposed substantially parallel to each other when the conventional foldable chair frame 1 is disposed at a folded position, as best shown in FIG. 3. These bends are aesthetically unappealing and complicate manufacturing of the conventional foldable chair frame 1. Moreover, the left and right fastening units 18 need to be loosened and tightened each time the conventional foldable chair frame 1 is disposed at a different position between the sitting and reclining positions, which is inconvenient for the user.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a foldable chair frame that can overcome the aforesaid drawbacks of the prior art.

According to the present invention, a foldable chair frame comprises a seat, a backrest, left and right armrests, left and right pivot joints, and front and rear legs. The backrest is coupled pivotably to the seat. Each of the left and right armrests is coupled pivotably to the backrest. Each of the left and right pivot joints is coupled to a respective one of the left and right armrests and has front and rear pivot portions. The front leg includes left and right rod members, each of which has an upper end coupled pivotably to the front pivot portion of a respective one of the left and right pivot joints. The rear leg includes left and right rod members, each of which has an upper end coupled pivotably to the rear pivot portion of a respective one of the left and right pivot joints.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:

FIG. 1 is a perspective view of a conventional foldable chair frame;

FIG. 2 is a schematic diagram illustrating the conventional foldable chair frame when disposed at a reclining position;

FIG. 3 is a schematic diagram illustrating the conventional foldable chair frame when disposed at a folded position;

FIG. 4 is a perspective view of the preferred embodiment of a foldable chair frame according to this invention;

FIG. 5 is a schematic partly sectional view illustrating an armrest of the preferred embodiment;

FIG. 6 is a schematic diagram illustrating the preferred embodiment when disposed at a sitting position;

FIG. 7 is a schematic diagram illustrating the preferred embodiment when disposed at a reclining position;

FIG. 8 is a schematic partly sectional view illustrating a state of the armrest when the preferred embodiment is disposed at the reclining position;

FIG. 9 is a fragmentary exploded perspective view illustrating a link unit of the preferred embodiment;

FIG. 10 is a schematic diagram illustrating the preferred embodiment when disposed at a folded position; and

FIG. 11 is a schematic diagram illustrating the preferred embodiment when disposed between the sitting and folded positions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 4, the preferred embodiment of a foldable chair frame according to this invention is shown to include a seat 21, a backrest 22, left and right armrests 3, left and right pivot joints 4, and front and rear legs 5, 6.

The seat 21 is generally U-shaped, and includes left and right seat members 211, 212, each of which has front and rear ends, and an interconnecting seat member 213 that interconnects the rear ends of the left and right seat members 211, 212 of the seat 21.

The backrest 22 includes left and right backrest members 221, 222, each of which is coupled pivotably to a respective one of the left and right seat members 211, 212 of the seat 21.

Each of the left and right armrests 3 is coupled pivotably to a respective one of the left and right backrest members 221, 222 of the backrest 22. Since the left and right armrests 3 are identical in structure, only the left armrest 3 will be described herein.

With further reference to FIG. 5, the left armrest 3 includes an elongated rod 32, a tubular member 33, a resilient member 34, and an abutting member 38. The elongated rod 32 has front and rear ends 321, 322. The tubular member 33 is sleeved movably on the elongated rod 32 and is disposed between the front and rear ends 321, 322 of the elongated rod 32. The resilient member 34, such as a compression spring, is sleeved movably on the elongated rod 32 and is disposed between the front end 321 of the elongated rod 32 and the tubular member 33.

The left armrest 3 further includes a cover member 37 and an arm support 31. The cover member 37 serves to cover the tubular member 33 and the resilient member 34 and has front and rear ends. In this embodiment, the cover member 37 includes left and right plates 371, 372 between which the tubular member 33 and the resilient member 34 are disposed and which cooperatively define the front and rear ends of the cover member 37.

The abutting member 38 interconnects, i.e., extends through, the front end of the cover member 37 and the front end 321 of the elongated rod 32.

The foldable chair frame further includes a first pivot pin 91 that extends through the rear end of the cover member 37, the rear end 322 of the elongated rod 32, and the left backrest member 221 of the backrest 22.

The arm support 31 is mounted on the cover member 37.

Each of the left and right pivot joints 4 is coupled to a respective one of the left and right armrests 3. Since the left and right pivot joints 4 are identical in structure, only the left pivot joint 4 will be described herein.

The left pivot joint 4 has front and rear pivot portions 421, 422, and includes left and right plates 42 that cooperatively define the front and rear pivot portions 421, 422 thereof, and a base plate 41 that interconnects the left and right plates 42 thereof and that is connected to the tubular member 33 of the left armrest 3.

Each of the front and rear legs 5, 6 serves to support the foldable chair frame on the ground (not shown).

The front leg 5 includes left and right rod members 51, each of which has upper and lower ends, and an interconnecting rod member 52 that interconnects the lower ends of the left and right rod members 51 thereof. The upper end of the left rod member 51 of the front leg 5 is coupled pivotably to the front pivot portion 421 of the left pivot joint 4. In particular, the upper end of the left rod member 51 of the front leg 5 is disposed between the left and right plates 42 of the left pivot joint 4. The foldable chair frame further includes a second pivot pin 92 that extends through the front pivot portion 421 of the left pivot joint 4 and the upper end of the left rod member 51 of the front leg 5.

The upper end of the right rod member 51 of the front leg 5 is coupled to the right pivot joint 4 in a similar manner the upper end of the left rod member 51 of the front leg 5 is coupled to the left pivot joint 4.

The rear leg 6 includes left and right rod members 61, each of which has upper and lower ends, and an interconnecting rod member 62 that interconnects the lower ends of the left and right rod members 61 thereof. The upper end of the left rod member 61 of the rear leg 6 is coupled pivotably to the rear pivot portion 422 of the left pivot joint 4. In particular, the upper end of the left rod member 61 of the rear leg 6 is disposed between the left and right plates 42 of the left pivot joint 4. The foldable chair frame further includes a third pivot pin 93 that extends through the rear pivot portion 422 of the left pivot joint 4 and the upper end of the left rod member 61 of the rear leg 6.

The upper end of the right rod member 61 of the rear leg 6 is coupled to the right pivot joint 4 in a similar manner the upper end of the left rod member 61 of the rear leg 6 is coupled to the left pivot joint 4.

In this embodiment, the left and right rod members 51, 61 of the front and rear legs 5, 6 are straight in shape.

The foldable chair frame further includes a footrest 8 that includes left and right footrest members 81, first and second pivot members 83, each of which couples pivotably an upper end of a respective one of the left and right footrest members 81 to the front end 321 of the elongated rod 32 of a respective one of the left and right armrests 3, and third and fourth pivot members 82, each of which couples pivotably a respective one of the left and right footrest members 81 to the front end of a respective one of the left and right seat members 211, 212 of the seat 21.

It is noted that when the foldable chair frame is disposed at a sitting position, as best shown in FIG. 6, the backrest 22 and the seat 21 define a first angle therebetween and the footrest 8 rests on the ground. At this position, as best shown in FIG. 5, the tubular member 33 is disposed distal from the abutting member 38 such that the resilient member 34 is in a relaxed state.

It is also noted that when the foldable chair frame is disposed at a reclining position, as best shown in FIG. 7, the backrest 22 and the seat 21 define a second angle therebetween larger than the first angle and the footrest 8 is raised from the ground. At this position, as best shown in FIG. 8, the tubular member 33 is disposed proximate to the abutting member 38 such that the resilient member 34 is in a compressed state.

From the above description, when it is desired to dispose the foldable chair frame from the sitting position to the reclining position, the backrest 22 may be simply rotated relative to the seat 21 by exerting an external force thereon, which in turn, pulls the elongated rod 32. This results in movement of the abutting member 38 toward the tubular member 33 against the biasing action of the resilient member 34, and rotation of the seat 21 relative to the rear leg 6, thereby raising the footrest 8 from the ground. At this position, when it is desired to dispose the foldable chair frame back to the sitting position, the backrest 22 is simply relieved from the external force. This results in movement of the abutting member 38 away from the tubular member 33 due to the biasing action of the resilient member 34, rotation of the backrest 22 relative to the seat 21, and rotation of the seat 21 relative to the rear leg 6, thereby lowering the footrest 8 on the ground.

From the foregoing, it is therefore readily apparent that the foldable chair frame of this invention can be disposed at different positions between the sitting and reclining positions by simply exerting different external forces on the backrest 22.

The foldable chair frame further includes left and right link units 7. Since the left and right link units 7 are identical in structure, only the left link unit 7 will be described herein.

Referring back to FIGS. 6 and 7 and with further reference to FIG. 9, the left link unit 7 includes first and second link members 71, 72, and a limiting member 73. Each of the first and second link members 71, 72 has opposite first and second ends. The foldable chair frame further includes a fourth pivot pin 94 that extends through the left rod member 51 of the front leg 5 and the first end of the first link member 71, a fifth pivot pin 95 that extends through the first end of the second link member 72, the second end of the first link member 71, and the left seat member 211 of the seat 21, and a sixth pivot pin 96 that extends through the left rod member 61 of the rear leg 6 and the second end of the second link member 72. The limiting member 73 extends from the second end of the first link member 71 in a direction away from the seat 21, is disposed behind the left rod member 61 of the rear leg 6, and abuts against the left rod member 61 of the rear leg 6 when the foldable chair frame is disposed at the sitting and reclining positions.

In this embodiment, as best shown in FIG. 6, the front pivot portion 421 of the left pivot joint 4 and the left armrest 3 define a first distance therebetween, and the rear pivot portion 422 of the left pivot joint 4 and the left armrest 3 define a second distance therebetween smaller than the first distance. As such, when the foldable chair frame is disposed at a folding position, as best shown in FIG. 10, the front and rear legs 5, 6 are disposed parallel to each other.

With further reference to FIG. 11, when it is desired to dispose the foldable chair frame from the sitting position to the folding position, the left and right armrests 3 are rotated relative to the backrest 22, which in turn, pulls the footrest 8. This results in rotation of the seat 21 relative to the backrest 22, rotation of the front leg 5 relative to the left and right pivot joints 4, and rotation of the left and right pivot joints 4 relative to the rear leg 6. While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements. 

1. A foldable chair frame, comprising: a seat; a backrest coupled pivotably to said seat; left and right armrests, each of which is coupled pivotably to said backrest; left and right pivot joints, each of which is coupled to a respective one of said left and right armrests and has front and rear pivot portions; a front leg including left and right rod members, each of which has an upper end coupled pivotably to said front pivot portion of a respective one of said left and right pivot joints; and a rear leg including left and right rod members, each of which has an upper end coupled pivotably to said rear pivot portion of a respective one of said left and right pivot joints.
 2. The foldable chair frame as claimed in claim 1, further comprising a left link unit including a link member that has opposite first and second ends, each of which is coupled pivotably to a respective one of said left rod member of said front leg and said seat.
 3. The foldable chair frame as claimed in claim 2, wherein said left link unit further includes a second link member that has opposite first and second ends, each of which is coupled pivotably to a respective one of said seat and said left rod member of said rear leg.
 4. The foldable chair frame as claimed in claim 3 further comprising a pivot pin that extends through said first end of said second link member of said left link unit, said second end of said link member of said left link unit, and said seat.
 5. The foldable chair frame as claimed in claim 2, wherein said left link unit further includes a limiting member that extends from said second end of said link member and that is disposed behind said left rod member of said rear leg.
 6. The foldable chair frame as claimed in claim 1, further comprising a right link unit including a link member that has opposite first and second ends, each of which is coupled pivotably to a respective one of said right rod member of said front leg and said seat.
 7. The foldable chair frame as claimed in claim 6, wherein said right link unit further includes a second link member that has opposite first and second ends, each of which is coupled pivotably to a respective one of said seat and said right rod member of said rear leg.
 8. The foldable chair frame as claimed in claim 7, further comprising a pivot pin that extends through said first end of said second link member of said right link unit, said second end of said link member of said right link unit, and said seat.
 9. The foldable chair frame as claimed in claim 6, wherein said right link unit further includes a limiting member that extends from said second end of said link member and that is disposed behind said right rod member of said rear leg.
 10. The foldable chair frame as claimed in claim 1, wherein said left armrest includes an elongated rod that has front and rear ends, said rear end of said elongated rod being coupled pivotably to said backrest, a tubular member sleeved movably on said elongated rod and disposed between said front and rear ends of said elongated rod, said left pivot joint being coupled to said tubular member, a resilient member sleeved movably on said elongated rod and disposed between said front end of said elongated rod and said tubular member, and an abutting member provided on said front end of elongated rod.
 11. The foldable chair frame as claimed in claim 10, wherein said left armrest further includes a cover member for covering said tubular member and said resilient member.
 12. The foldable chair frame as claimed in claim 1, wherein said right armrest includes an elongated rod that has front and rear ends, said rear end of said elongated rod being coupled pivotably to said backrest, a tubular member sleeved movably on said elongated rod and disposed between said front and rear ends of said elongated rod, said right pivot joint being coupled to said tubular member, a resilient member sleeved movably on said elongated rod and disposed between said front end of said elongated rod and said tubular member, and an abutting member provided on said front end of elongated rod.
 13. The foldable chair frame as claimed in claim 12, wherein said right armrest further includes a cover member for covering said tubular member and said resilient member.
 14. The foldable chair frame as claimed in claim 1, further comprising a footrest coupled pivotably to said left and right armrests and said seat.
 15. The foldable chair frame as claimed in claim 1, wherein said left pivot joint includes left and right plates that cooperatively define said front and rear pivot portions thereof, said upper ends of said left rod members of said front and rear legs being disposed between said left and right plates of said left pivot joint.
 16. The foldable chair frame as claimed in claim 1, wherein said right pivot joint includes left and right plates that cooperatively define said front and rear pivot portions thereof, said upper ends of said right rod members of said front and rear legs being disposed between said left and right plates of said right pivot joint.
 17. The foldable chair frame as claimed in claim 1, wherein said front pivot portion of said left pivot joint and said left armrest define a first distance therebetween, and said rear pivot portion of said left pivot joint and said left armrest define a second distance therebetween smaller than the first distance.
 18. The foldable chair frame as claimed in claim 1, wherein said front pivot portion of said right pivot joint and said right armrest define a first distance therebetween, and said rear pivot portion of said right pivot joint and said right armrest define a second distance therebetween smaller than the first distance. 